Page 1282 - Advanced Organic Chemistry Part B - Reactions & Synthesis

1258 compounds, including those lacking a particular substituent (skip) (4 aldehydes ×2
morpholines ×1 oxindole)= 8 core structures × 1 + 8 × 12 × 4 = 3104 different
CHAPTER 13 68
compounds. A version of the chemical tagging method was used for coding the beads.
Multistep Syntheses Analysis of a sample of the beads indicated that at least 82% of them contained the
desired compound in greater than 80% purity.
The epothilone synthesis in Scheme 13.59 (p. 1221) has been used as the basis
for a combinatorial approach to epothilone analogs. 69 The acyclic precursors were

Fig. 13.3. Radio-frequency tagging of microreactors for combinatorial
synthesis on a solid support. Reproduced from K. C. Nicolaou, X.-Y. Xiao,
Z. Parandoosh, A. Senyei, and M. P. Nova, Angew. Chem. Int. Ed. Engl.,
34, 2289 (1995), by permission of Wiley-VCH.

68 H. B. Blackwell, L. Perez, R. A. Stavenger, J. A. Tallarico, E. Cope-Etough, M. A. Foley, and S. L.
Schreiber, Chem. Biol., 8, 1167 (2001).
69
K. C. Nicolaou, N. Wissinger, J. Pastor, S. Ninkovic, F. Sarabia, Y. He, D. Vourloumis, S. Yang,
T. Li, P. Giannakakou, and E. Hamel, Nature, 387, 268 (1997); K. C. Nicolaou, D. Vourloumis, T.